1. Field of the Invention
The invention relates to a printed wiring board and, more particularly, to a printed wiring board having sections comprising laminates with different dissipation factors.
2. Brief Description of Prior Developments
A printed wiring board (PWB) has a substrate comprised of an epoxy resin laminate. Modern mobile telephones can have one or more antenna integrated on or as an integral part of a PWB. The antenna may be an integral part of the PWB or it may be located above a surface of the PWB or other conductive member providing a ground plane. Various different substrates are available for an integrated antenna PWB substrate which can minimize parasitic loss (such as heat) that results from subjecting the dielectric material of the substrate to an alternating electric field. Dissipation factor is a measurement of this parasitic loss. Loss tangent is effectively the same as dissipation factor, they take slightly different views which are useful when designing different types of circuits. Conventional materials, such as FR-4 for example, have been used for mobile telephone PWB substrates because of their dielectric constant and dissipation factor to enable support of the antenna on the mobile telephone PWB substrate. For example, FR-4 has a dielectric constant (Dk) of about 4.5-4.9 and a dissipation factor (Df) of about 0.013-0.020. Newer telephone radio standards, such as 3G and 4G for example, use RF frequencies above 1 GHz, such as 2 Ghz and above. Conventional integrated antenna PWB substrates are not suited for integral antenna application with these higher RF frequencies due to their relatively high dielectric constants (Dk or Er) and loss (Df or tan δ).